[Elecraft] mic

[Dwayne Rohmer]

Skip,

I converted an '80's era H10-40A David Clark aviation headset. Adapting 
it for use with the K3 required a complete rebuild. The microphone isn't 
the only issue. The headband, domes, and mike boom can be salvaged, but 
you may want to consider replacing the remaining parts.

The original aviation spec microphone is not a good match for amateur 
radio. Consider replacment with an Acousticom 5730-CA electret, a 
communications mike that works well with the K3. It's an easy fit to the 
David Clark wire boom, not expensive, and produces good audio with TX EQ 
settings set to "0".

The original earphones were wired for 150 ohms (300 ohms each, wired in 
parallel, mono audio). They were replaced with original David Clark 19 
ohm, Part# 10376G-30, available on ebay for $12.00 each. The earphone 
frequency response is 200 - 5500 Hz, excellent for CW and SSB, forget 
the ipod.

To use the two speaker output of the K3, you'll have to replace the 
original headset wiring to provide separate audio to each earphone. 
Acousticom also has a wire assembly with microphone wires and stereo 
speaker wires in one outer jacket, separated on one end to attach two 
3.5mm plugs that you need for the K3.

The original foam ear seals were broken down from age. They didn't seal 
well, and extended wear caused ear pain. They were replaced with the gel 
filled type.  Gel seals won't compress, are more comfortable, and 
provide a better seal from noise.

I wouldn't recommend this if you have to purchase an old headset, but if 
you already have one and want to put it to use, the rebuild may be worth 
considering. When you get done, you'll have a decent headset that can be 
used in a noisy environment.

73,

Dwayne WV5I


On 6/11/2017 3:29 PM, Fred Jensen wrote:
> Just curious ... I inherited a David Clark noise cancelling aviation 
> headset/mic from a neighbor who was a US Forest Service pilot. I've 
> never tried it, the connector is strange.  I'm not even sure I know 
> where it is right now.  Will it work with my K3 if I can find it and 
> get the connector compatible?  I know they're expensive.
>
> Maybe it will cancel the powerline noise on 80? [:-))
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 6/11/17 12:55 PM, Joe Subich, W4TV wrote:
>>
>> On 6/11/2017 2:45 PM, kevino z wrote:
>>> Although headsets like my Heil Pro 7 may be more money, am I really
>>> "wasting" money on buying a "fancy brand name"  considering the
>>> unit consists of mic and incredible speakers?
>>
>> Yes, at about $250 retail (plus adapter cable), the Pro 7 is more than
>> five times as expensive as the Yamaha CM-500 (electret mic), Koss SB40
>> (dynamic mic) or SB45 (electret mic) headsets.   Both the Yamaha and
>> Koss headsets have outstanding 120 Ohm headset drivers with sensitivity
>> rated at 96dB/mW and microphones well tailored for voice work. Heil
>> does not even publish the impedance or sensitivity for their headset
>> drivers!
>>
>> For the price of a Heil Pro 7 one could get a Broadcast headset like
>> the Audio Technica BPHS1 ($199), Sennheiser HMD280 ($249) or Shure
>> BRH440M ($249) - all of which are significantly higher quality than
>> the Pro7 (and field proven).
>>
>> 73,
>>
>>    ... Joe, W4TV
>
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